<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="java.io.*,java.util.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>User Agent Example</title>
</head>
<body>
	<center>
		User Agent Example
	</center>
	<br>el表达式不针对 jsp声明的普通变量只针对特定的jsp对象 例如pageContext、request、session和application
	<br>EL的内置对象 不同于jsp内置对象
	<h1>${title}</h1>
	<div align="center">
		<p>${header["user-agent"]}</p>
	</div>
</body>
</html>